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Diversity and evolution of mitochondrial RNA editing systems
1Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, B3H 1X5, Canada. M.W.Gray@Dal.Ca
IUBMB Life
|July 26, 2003
Summary
RNA editing, the programmed alteration of RNA sequences, challenges genetic principles by changing encoded proteins. This phenomenon, observed in eukaryotes, arises within specific lineages, prompting questions about its evolution and function.
Area of Science:
- Molecular Biology
- Genetics
- Evolutionary Biology
Background:
- RNA editing involves programmed alterations to RNA nucleotide sequences, differing from the encoding DNA.
- It includes insertion/deletion and substitution patterns, affecting RNA colinearity with DNA.
- This process occurs in various RNA types (mRNA, rRNA, tRNA, viral RNA) primarily in eukaryotic mitochondria.
Purpose of the Study:
- To define RNA editing and its mechanisms.
- To explore the implications of RNA editing on genetic information flow.
- To investigate the evolutionary origins and distribution of RNA editing systems.
Main Methods:
- Review of existing literature on RNA editing phenomena.
- Analysis of RNA sequence variations relative to DNA templates.
- Phylogenetic analysis of RNA editing system distribution.
Main Results:
- RNA editing can alter encoded amino acids and create/eliminate translation signals.
- It contradicts the direct predictability of protein sequences from gene sequences.
- RNA editing systems show narrow phylogenetic distributions, suggesting derived origins.
Conclusions:
- RNA editing represents a significant departure from established genetic dogma.
- Its derived nature within specific lineages raises questions about its emergence and fixation.
- Further research is needed to understand the evolutionary drivers and functional significance of RNA editing.